I replaced my galley laminated counter tops with 1/4” thick corian. I have a new modern sink that instead of under mounting is sandwiched between the corian and the marine ply that made up the original countertop. Other than a few specific tools required to complete the job it’s not super difficult. I’d say the whole project was around $800.
There are several cruiser friends in the Caribbean who have done this. They look fantastic. They are heavy. Find a well skilled installer who has some experience. Look at some of his work.